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Effects of Chronic Intake of Cannabis on Contrast Sensitivity

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ClinicalTrials.gov Identifier: NCT01793961
Recruitment Status : Completed
First Posted : February 18, 2013
Last Update Posted : July 12, 2019
Sponsor:
Information provided by (Responsible Party):
University Hospital, Strasbourg, France

Brief Summary:

Rates of driving under the influence of cannabis have risen in recent years. Cannabis is involved in 1/3 of motor vehicle collisions. The chronic use of cannabis is known to affect dopaminergic regulation and may thus impair contrast sensitivity. In turn, contrast sensitivity disorders could originate difficulties to anticipate and avoid collision with objects, especially when objects are in movement. The investigators goal is to examine the effects of a chronic intake of cannabis on contrast sensitivity. The observed values will be compared to standard references. In addition, since smoking cannabis is always associated with tobacco, the investigators will control the effects of tobacco on contrast sensitivity.

In this study, the investigators will include 36 cannabis addicts, 36 tobacco addicts and 36 no smokers. The investigators will present gratings with different spatial frequencies and the investigators will determine contrast thresholds for static and dynamic (moving) gratings. The investigators predict that cannabis addicts will present abnormal contrast sensitivity especially in case of dynamic presentation of gradings.


Condition or disease Intervention/treatment Phase
Cannabis Dependence Other: electroretinogram Other: contrast sensitivity tests Not Applicable

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 95 participants
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Other
Official Title: Effects of Chronic Intake of Cannabis on Contrast Sensitivity
Actual Study Start Date : March 22, 2013
Actual Primary Completion Date : November 30, 2015
Actual Study Completion Date : September 10, 2018

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Allergy Marijuana

Arm Intervention/treatment
"Cannabis" Arm
patient addicted to cannabis
Other: electroretinogram
Other: contrast sensitivity tests
"Tobacco" Arm
patient addicted to tobacco
Other: electroretinogram
Other: contrast sensitivity tests
"Healthy volunteers"
no smokers
Other: electroretinogram
Other: contrast sensitivity tests



Primary Outcome Measures :
  1. The contrast detection treshold [ Time Frame: up to 9 days after inclusion ]
    Comparison of the contrast detection threshold of the 3 groups



Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 50 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

"Cannabis" Arm

  • patient addicted to cannabis
  • Positive CAST test result
  • Urine tested positive for cannabis metabolites

"Tobacco" Arm

  • positive Fagerström test result
  • No cannabis intake in the last year before inclusion
  • No previous history of cannabis use

"Healthy Volunteers"

  • No tobacco or cannabis intake in the last year before inclusion
  • No history of addictive disorders

Exclusion Criteria:

  • addiction to other substances than cannabis or tobacco
  • benzodiazepine treatment
  • patient with history of benzodiazepine treatment
  • patient with history of general anesthesia in the last 3 months before inclusion
  • patient with history of head trauma
  • Pregnant woman
  • breast feeding woman
  • Adults under supervision or guardianship

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Responsible Party: University Hospital, Strasbourg, France
ClinicalTrials.gov Identifier: NCT01793961    
Other Study ID Numbers: 5331
2012-A00991-42 ( Other Identifier: n° IDRCB )
First Posted: February 18, 2013    Key Record Dates
Last Update Posted: July 12, 2019
Last Verified: July 2019
Additional relevant MeSH terms:
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Marijuana Abuse
Substance-Related Disorders
Chemically-Induced Disorders
Mental Disorders